POWER ELECTRONICS HANDBOOK
Can a three-phase power supply operate from wye and delta ac inputs? TDK LAMBDA TECHNICAL MARKETING
A few guidelines help clarify what three-phase input voltage best suits a particular large power system. AC-DC POWER SUPPLIES rated higher than 2.5 kW frequently have a three-phase ac input. In the U.S. the voltage can be 208/220 Vac or 480 Vac. In Europe it is a “harmonized 400 Vac” which really is 415 Vac in the U.K. and 380 Vac for Europe. A higher input voltage allows more power to be drawn from the incoming ac at a lower
An HWS1800T-24 three-phase power supply.
current. These three-phase ac voltages can be one of two configurations – delta or wye (pronounced “why”). Typically high-voltage power is transmitted from the power generation plants to local substation transformers (where it is reduced in voltage) and then to facilities in a delta configuration. Note that a delta configuration only uses three wires and has no neutral or ground wire. This saves the cost of a fourth wire, which is unneeded during transmission. Consider the U.S. first. At a typical large power consumer such as a factory, a 480-Vac delta threewire feed enters the facility. (It comes to the facility from the local utility substation.) From the facility’s incoming distribution panel, 480 Vac delta is supplied
A TPS4000-24 three-phase power supply.
Genesys+ programmable power supplies GH1.5kW / G1.7kW
1ø 85 to 265Vac
G2.7kW / G3.4kW:
1ø 170 to 265Vac or 3ø 208Vac or 3ø 400Vac
G5kW / GSP10kW & 15kW: 3ø 208Vac, or 3ø 400Vac or 3ø 480Vac
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DESIGN WORLD — EE NETWORK
2 • 2020
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